1. Field of the Invention
The present invention relates to a cassette loading device for an image forming apparatus, and more particularly, it relates to an automatic cassette loading device which is arranged in a sheet feeding portion of an image forming apparatus such as a copying machine, printing machine, laser printer and the like which can automatically load or unload a "cassette" accommodating number of sheets with respect to the image forming apparatus. Here, the wording "cassette" is used as a general term for indicating all of sheet accommodating means to be available, and, therefore, in the present invention, the sheet accommodating means is not limited to the so-called removable box-shaped cassette.
2. Related Background Art
In the past, copying machines including removable cassettes therein have been known. Such conventional copying machines are generally grouped into two types: first type is a side loading type wherein the cassette is retracted in a direction opposite to a sheet feeding direction, and second type is a front loading type wherein the cassette is retracted in a direction perpendicular to the sheet feeding direction. In the copying machine of the front loading type, the cassette is slidably supported by guide rails and the like. Recently, the copying machines of the front loading type have been increased for the reasons that (1) less installation space required, (2) the sheet can be replenished without unloading the cassette, (3) the cassette can easily be handled at a front side, and the like.
However, the above-mentioned conventional copying machine of the front loading type, there arose problems that the structure of the machine was complicated and it was difficult and troublesome to position the cassette with respect to the body of the copying machine, since a cassette support, the slidable guide rails and the like were used for slidably supporting and guiding the cassette.
Particularly, in the copying machine of automatic loading type wherein the cassette is automatically loaded and unloaded, there arose problems that the positioning of the cassette was more complicated, that it was difficult to separate the cassette from a driving means, and that it was difficult to change the cassettes.